UK parliamentary by-elections since 1945
This list notes the number of by-elections by session since 1945-46 together with a list of the the successful candidates in by-elections since 2005.

Peru held a general election on 11 April 2021. No single presidential candidate gained a majority of votes cast, so run-off poll was held on 6 June, with Pedro Castillo securing a narrow victory.
Peru: 2021 presidential election (584 KB , PDF)
Peru’s general election was to elect a President, two Vice-Presidents and members of the 130-seat Congress.
The country’s National Office of Electoral Processes (ONPE) initially registered 22 candidates to contest the Presidency; however, by the time of the election, only 18 stood.
Opinion polls suggested none of the candidates would secure enough votes for an outright victory in the first round, with only seven likely to contest the run-off poll two months later.
The election took place under the cloud of the Covid-19 pandemic. The Government’s response to the pandemic and the worsening economic situation were key factors for voters, as well as ever-present concerns about corruption.
As expected, no candidate won the 50 per cent of votes required for an outright victory, so a run-off poll between the top two candidates – Pedro Castillo and Keiko Fujimori – was held on 6 June.
Early results showed Castillo had secured a narrow victory, but Fujimori challenged the result and it took six weeks for Peru’s National Electoral Jury to announce the official result.
Castillo won the election by a slim majority and will be sworn in as president on 28 July, the country’s fifth president in as many years.
Peru: 2021 presidential election (584 KB , PDF)
This list notes the number of by-elections by session since 1945-46 together with a list of the the successful candidates in by-elections since 2005.
A Westminster Hall debate on returning forcibly deported children to Ukraine is scheduled for Wednesday 21 May 2025, from 2.30pm to 4.00pm. The debate will be led by Johanna Baxter MP.
How is UK defence responding to increasing geopolitical competition in the Arctic/ High North?